Merge pull request #241 from ethereum/vmtester

vmtester: dereference if output_data is present

test/vmtester/tests.cpp

@@ -10,6 +10,24 @@
 #include <array>
 #include <cstring>
 
+namespace
+{
+// NOTE: this is to avoid compiler optimisations when reading the buffer
+uint8_t read_uint8(const volatile uint8_t* p)
+{
+    return *p;
+}
+
+void read_buffer(const uint8_t* ptr, size_t size)
+{
+    for (size_t i = 0; i < size; i++)
+    {
+        read_uint8(&ptr[i]);
+    }
+}
+
+}  // namespace
+
 TEST_F(evmc_vm_test, abi_version_match)
 {
     ASSERT_EQ(vm->abi_version, EVMC_ABI_VERSION);
@@ -46,6 +64,11 @@ TEST_F(evmc_vm_test, execute)
     {
         EXPECT_EQ(result.output_size, 0);
     }
+    else
+    {
+        EXPECT_NE(result.output_size, 0);
+        read_buffer(result.output_data, result.output_size);
+    }
 
     if (result.release)
         result.release(&result);